Graft copolymers of lactone polyesters

ABSTRACT

Various ethylenically unsaturated monomers can be graft copolymerized onto lactone polyesters, such as, homopolymers of Epsilon -caprolactone or copolymers of Epsilon -caprolactone and Epsilon -alkyl- Epsilon -caprolactones at temperatures between 90* and 150* C. The resultant graft copolymers can be used as plasticizers for polyvinyl chloride resins.

Unite States Critchfield et al.

[451 May 20, 1975 GRAFT COPOLYMERS OF LACTONE POLYESTERS inventors:Frank E. Critchfield; Joseph V.

Koleske, both of Charleston, W. Va.

Assignee: Union Carbide Corporation, New

York, NY.

Filed: Feb. 8, 1974 Appl. No.: 440,779

Related U.S. Application Data Division of Ser No. 273,300, July 19,1972, which is a division of Ser. No. 109,982, July 26, 1971, Pat. No.3,760,034.

U.S. C1. 260/899; 117/132; 117/161; 260/296 F; 260/29.6 NR; 260/29.6 T;260/874; 260/876 R; 260/895; 260/898; 260/900; 260/901 Int. Cl. C08f29/24 Field of Search 260/899, 876, 874

[56] References Cited UNITED STATES PATENTS 3,418,393 12/1968 King260/874 X 3,592,877 7/1971 Mullins 1 260/874 3,598,799 8/1971 Naylor260/874 X Primary Examiner-Murray Tillman Assistant ExaminerC. J.Seccuro Attorney, Agent, or FirmBernard Francis Crowe [57] ABSTRACT 8Claims, No Drawings GRAFT COPOLYMERS OF LACTONE POLYESTERS BACKGROUND OFTHE INVENTION This invention pertains to graft copolymers of lac- 5 tonepolyesters and more particularly to copolymers obtained with lactonepolyesters and ethylenically unsaturated monomers.

Although lactone polyesters have shown considerable potential in thepolymer industry they have been found to be somewhat deficient asadhesives to various substrates. In vinyl resin technology theseinteresting polymers were found to evince excellent plasticizingproperties but their tendency to crystallize upon storage caused theirseparation from the base resin.

It is therfore an object of this invention to enhance the adhesiveproperties of lactone polyesters.

It is another object of this invention to modify the tendency of lactonepolyesters to crystallize in vinyl resin compositions.

It is still another object of this invention to prepare graft copolymersof lactone polyesters, such as e-caprolactone homopolymer or, copolymersof e-alkyl-ecaprolactone.

SUMMARY OF THE INVENTION CH2=CR' wherein R is a monovalent radical suchas hydrogen, halogen or methyl and R is a monovalent radical such asCOOH, COOR",

Examples of ethylenically unsaturated monomer which are suitable forgraft polymerization onto lactone polyester backbones include alkylacrylates having up to 18 carbon atoms in the alkyl group, alkylmethacrylates containing up to 18 carbon atoms in the alkyl group,styrene, vinyl halides, vinylidene halides, alkali metalar(methacryloxyethoxy) benzene sulfonates, alkali metalar-(acryloxyethoxy)benzene sulfonates, N-methyl-N-vinyl acetamide,alkali metal vinyl benzene sulfonates, vinyl pyridines, lower alkylsubstituted vinyl pyridines, dialkylaminoalkyl acrylates ormethacrylates, acrylonitrile, methacrylonitrile, vinyl esters ofaliphatic acids, the latter containing up to about 18 carbon atoms, andalpha, beta-ethylenically unsaturated carboxylic acids, and the like.

Representative alkyl acrylates which can be used as the ethylenicallyunsaturated monomer in the abovedescribed graft copolymerization includemethyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, tetradecyl acrylate, octadecylacrylate, and the like. Representative alkyl methacrylates which can beused as ethylenically unsaturated monomers in the above-described graftcopolymerization include methyl methacrylate, ethyl methacrylate,isopropyl methacrylate, n-butyl methacrylate, octyl methacrylate, decylmethacrylate, lauryl methacrylate, octadecyl methacrylate, and the like.

Representative vinyl halides include vinyl chloride, vinyl fluoride,vinyl bromide and vinyl iodide. Representative vinylidene halidesinclude vinylidene chloride, vinylidene fluoride, vinylidene bromide andvinylidene iodide.

Preferred dialkylaminoalkyl acrylates and methacrylates which can begrafted onto the lactone polyesters include dimethylaminoethylmethacrylate, diethylaminoethyl acrylate, diethylarninoethyl acrylate,and the like.

Representative vinyl pyridines which can be graft co- ,S0 -a1ka1i. metalI halogen, phenyl or pyridyl, R" being an alkyl radical O polymerizedwith the lactone polyesters include 2-vinyl containing 1 to about 18carbon atoms and R being an alkylene radical containing 1 to about 6carbon atoms.

The grafting of ethylenically unsaturated monomers onto lactonepolyesters can be accomplished by heating lactone polyesters having amolecular weight of about 5,000 to 150,000 and a reduced viscosity ofabout 0.2 to 2.0 dl./gm. (measured as a 0.2% solution in benzene at30C.) with about 1 to about 20% by weight of an ethylenicallyunsaturated monomer and pyridine, 4-vinyl pyridine, 2-methyl-5-vinylpyridine, and the like. 7

Vinyl esters which can be graft copolymerized with the lactonepolyesters include vinyl formate, vinyl acetate, vinyl propionate, andthe like.

Alpha, beta-ethylenically unsaturated acids which can be copolymerizedwith the lactone polyesters include acrylic acid, methacrylic acid,maleic acid, crotonic acid, itaconic acid, and the like.

Although it is preferred to employ polymerization times of about 2 to 3hours, this period can range from about 0.5 to 5 hours if desired.

Polymerization pressure can vary and subatmospheric or superatmosphericpressures can be used as well as ambient atmospheric pressures.

Although the preferred temperature range is about to about C.,temperatures as low as about 40 C. and as high as about 250 C. can beused if desired.

The instant process can be carried out as a batch or continuous process.

The preferred free radical polymerization initiators are organicperoxides having a half-life of about 0.5 to 2 hours in the temperaturerange of about 90 to about 160C. Specific preferred organic peroxidesinclude dit-butyl peroxide, dicumyl peroxide, dibenzoyl peroxide and thelike.

In addition to the process variable discussed above, viz.,polymerization temperature, polymerization free radical initiator, andinitiator concentration, the mode of addition of the vinyl comonomer andinitiator was also investigated. It was found preferable to add theinitiator-vinyl monomer mixture dropwise over the course of severalhours to the lactone polyester rather than all at once.

The lactone polyester substrates used in the formation of the graftcopolymers of this invention can be made by processes well known in theart such as disclosed in U.S. Pat. No. 3,284,417 which is incorporatedherein by reference.

The lactone polyesters used in this invention can be described as havingrepeating units represented by the formula wherein R is H or an alkylgroup containing one to about six carbon atoms and n is an integerhaving a value of at least three, e.g., from three to six. The preferredlactone polyester is poly(e-caprolactone) although copolymers ofe-caprolactone and an e-alkyl-ecaprolactone, the latter containing aboutto about 90 weight percent of e-caprolactone copolymerized therein, canalso be used.

The lactone polyester graft copolymers of this invention can be used inmany diverse applications. For example, acrylic acid or methacrylic acidpoly(ecaprolactone) graft copolymers show excellent low temperatureadhesion to metallic substrates. The effiacy of poly(e-caprolactone) asa plasticizer for polyvinyl chloride can be enhanced as to the clarityof the plasticized polyvinyl chloride by grafting alkyl acrylic ormethacrylic esters or vinyl esters of aliphatic acids onto thepoly(e-caprolactone) backbone thus retarding or even eliminating thecrystallization of the poly(ecaprolactone). Acrylic acid or methacrylicacid poly(ecaprolactone) graft copolymers can be readily emulsified foruse as coatings or textile sizing agents.

In general the graft copolymers of this invention can also be used asdye assistants for textile fibers and as plasticizers for polyvinylchloride resins. In this application it is preferred to use polyblendscontaining about 10 to about 100 parts of graft copolymer per hundred ofpolyvinyl chloride resin with a range of about 30 to 90 being morepreferred. The alkali metal benzene sulfonates described above areparticularly useful as dye assistants for such difficult to dye fibersas polypropylene, polyethylene terephthalates, nylon and the like. Whengraft copolymers containing sodium ar- (methacryloxyethoxy)benzenesulfonate was blended with such fibers, they were successfully dyed withdisperse and basic dyes. Specific dyes which were used included LatylOrange 3R, Celliton Fast Red GGA, Eastman Fast Yellow GLF, EastmanPolyester Red 26, and Sevron Blue 56.

A further advantage in the use of acrylic acid ester or vinyl esterpolycaprolactone graft copolymers as plasticizers for polyvinyl chlorideresins was demonstrated by reduced aging phenomena.

The invention is further described in the Examples which follow. Allparts and percentages are by weight unless otherwise specified.

EXAMPLE 1 A sample of poly(e-caprolactone) for use as the lactonepolyester backbone substrates for grafting vinyl monomers was preparedby heating a closed 40 gallon reactor charged with about 20 gallons ofe-caprolactone monomer containing 1.0 weight per cent of diethyleneglycol, 300 parts of water per million parts of e-caprolactone, and 400parts of stannous dioctanoate per million parts of e-caprolactone, for 1hour at 150 C. and then for 6 hours at 180 C. The resultantpoly(ecaprolactone) had a number average molecular weight of about10,000 and a reduced viscosity (measured as a 0.2% solution in benzeneat 30 C.) of 0.3 dl/gm.

In a 500 ml 3necked, resin flask equipped with stainless steelanchor-type stirrer, gas inlet tube, thermometer, reflux condenser, andaddition funnel was charged 200 grams of the poly(e-caprolactone)prepared above. The flask was heated to an internal temperature of aboutC. which melted the poly(e-caprolactone) and then 11.3 grams (0.15 mole)of acrylic acid was added all in one portion. Then 1.7 grams (7millimoles) of dibenzoyl peroxide was added slowly to the mixture underan atmosphere of dry argon. The resulting mixture became very milky inappearance although the viscosity did not appear to change appreciably.After 2.5 hours the melt was poured out of the reaction flask andallowed to cool overnight. The reduced viscosity of the acrylicacid-poly(ecaprolactone) graft copolymer ob tained was found to be 0.3dl/gm. when measured as a 0.2% solution in benzene at 30 C. Theefficiency of grafting of the acrylic acid monomer onto thepoly(ecaprolactone) substrate was 27%. This determination was made byextracting the ground graft poly(scaprolactone) copolymer with methanolin a Soxhlet extraction apparatus, the methanol being a solvent forpolyacrylic acid, and then titrating a weighed portion of the dried andextracted grafted poly( e-caprolactone) potentiometrically withtetrabutylammonium hydroxide.

EXAMPLE 2 The procedure described in Example 1 was repeated with theexception that 1.7 grams of dicumyl peroxide (6.2 millimoles) wassubstituted for the dibenzoyl peroxide and the polymerizationtemperature was C. The resultant acrylic acid-poly(e-caprolactone) graftcopolymer had a reduced viscosity when measured as above, of 0.29 dl/gm.and the graft efficiency was 52%.

EXAMPLE 3 Example 2 was repeated with the exception that 20 grams (0.28moles; 10% based on the weight of poly(c caprolactone) of acrylic acidwas used. The resultant acrylic acid-poly(e-caprolactone) graftcopolymer had a reduced viscosity of 0.30 dl/gm. and a graft efficiencyof 34%.

EXAMPLE 4 Example 3 was repeated with the exception that 3 grams l2millimoles) of dicumyl peroxide was used, as the initiator. The reducedviscosity of the resultant acrylic acidpoly( e-caprolactone) graftcopolymer was 0.39 dl/gm., and the graft efficiency was 28%. Unlike theprevious examples this product showed considerable branching.

EXAMPLE 5 Example 3 was repeated with the exception that the acrylc acidmonomer was added dropwise over a period of 2 hours rather than in 1portion. The resultant acrylic acid-poly( e-caprolactone) graftcopolymer showed a reduced viscosity of 0.30 dl/gm. and a graftefficiency of 45%. There was some branching in the product butconsiderably less than that obtained in Example 4.

EXAMPLE 6 Example 3 was repeated with the exception that 0.8 grams (3millimoles) of dicumyl peroxide was used as the initiator and theacrylic acid monomer was added dropwise over a period of 2 hours ratherthan in one portion. The resultant acrylic acid-poly(ecaprolactone)graft copolymer had a reduced viscosity of 0.28 dl/gm. and was obtainedin a graft efficiency of 44%. In comparison with Examples 3 and 4 thisproduct showed little or not branching.

EXAMPLE 7 Example 3 was repeated with the exception that 1.0 grams (7millimoles) of di-t-butyl peroxide was used as the initiator in place ofthe dicumyl peroxide and the acrylic acid monomer was added in 5 cc.portions over a period of 2 hours. The reduced viscosity of this productwas 0.29 dl/gm. and the graft efficiency was 45%. This product showedlittle or no branching.

EXAMPLE 8 A higher molecular weight sample of poly(ecaprolactone) wasprepared by heating a 40 gallon reactor charged with 20 gallons ofe-caprolactone monomer containing 600 parts of water per million partsof e-caprolactone, and 2,000 parts of stannous dioctanoate per millionparts of e-caprolactone, to 150 C. for 1 hour and then 180 C. for 6hours. The resultant poly(e-caprolactone) had a weight average molecularweight of about 40,000 and a reduced viscosity (measured as a 0.2%solution in benzene at 30 C.) of about 0.65 dl/gm.

Using the procedure and apparatus described in Example l, 200 grams ofthe poly(e-caprolactone) prepared as described in the precedingparagraph was grafted with 6 grams (0.08 moles; 3%) of acrylic acidmonomer added dropwise over a period of 2 hours using 0.2 grams (0.74millimoles; 0.1%) of dicumyl peroxide as polymerization initiator at atemperature of 140 C. The resultant acrylic acid-poly(ecaprolactone)graft copolymer had a reduced viscosity of 0.55 dl/gm.

EXAMPLE 9 Using the apparatus and procedure described in Example 1 200grams of poly(e-caprolactone) having a reduced viscosity of 0.3 wasgraft polymerized with 20 grams (0.2 moles) of methyl methacrylatemonomer added in one portion at a temperature of 95 C. with apolymerization time of 3 hours and using 3.4 grams l4 millimoles) ofdibenzoyl peroxide as the polymerization initiator. The resultant methylmethacrylatepoly(e-caprolactone) graft copolymer showed a reducedviscosity of 0.37 dl/gm.

EXAMPLE 10 Example 9 was repeated with the exception that 1.0 grams (4millimoles) of dicumyl peroxide was used in place of dibenzoyl peroxideand the polymerization temperature was C. and the polymerization time 3hours. The resultant methyl methacrylate-poly(ecaprolactone) graftcopolymer showed a reduced viscosity of 0.37 dl/gm.

EXAMPLE 1 1 Example 10 was repeated with the exception that 40 grams(0.4 moles) of methyl methacrylate was used. The resultant methylmethacrylate-poly( ecaprolactone) graft copolymer showed a reducedviscosity of 0.43 dl/gm.

The efficacies of the graft copolymer prepared in Examples 9, l0 and l 1were compared as plasticizers for polyvinyl chloride, having a inherentviscosity of 0.63 dl/gm. (measured in accordance with ASTM D-1243- 60,Method A), with ungrafted poly(e-caprolactone) having a reducedviscosity of 0.3 dl/gm. To this end, the aforesaid polyvinyl chloridewas plasticized with 50% of each of Examples 9, 10 and 1 1 and ungraftedpoly(ecaprolactone) as Control A, by blending these components on aWiley two roll mill with a small amount of barium-cadmium stearate heatstabilizer for 15 minutes at C. and then pressing a small portion into afilm in a hydraulic press at C. and 25,000 psi. The ungraftedpoly(e-caprolactone)-polyvinyl chloride composition developed a hazeafter 3 hours indicative of the on-set of crystallization of theungrafted polycaprolactone. In contrast the graft poly(ecaprolactone)copolymers prepared in Examples 9 and 10 afforded polyvinyl chloridefilms which took 10 hours before haziness was first observed and thegraft copolymer prepared in Example 1 1 afforded a polyvinyl chloridefilm which required 36 hours before the first haziness was developed.

EXAMPLE l 2 Using the procedure and apparatus described in Example 1,200 grams of poly(e-caprolactone) having a reduced viscosity of 0.3dl/gm. was graft copolymerized with 30 grams (0.35 moles) of vinylacetate monomer,

added in one portion, with 1.0 grams (4 millimoles) of dicumyl peroxideusing a polymerization temperature of 145 C. and a polymerization timeof 3 hours. The resultant vinyl acetate-poly(e-caprolactone) graftcopolymer showed a reduced viscosity of 0.35 dl/gm. When polyvinylchloride, having an inherent viscosity of 0.63 dl/gm. (ASTM D-1243-60,Method A) was plasticized as described above in Example 1 1 with 50% byweight of the vinyl acetate-poly(e-caprolactone) graft copolymer andpressed into a film, the resultant plasticizer composition required 50hours before the on-set of haziness.

EXAMPLE 13 Using the apparatus and procedure described in Example 1, 200grams of poly( e-caprolactone) having a reduced viscosity of 0.3 wasgraft polymerized with 40 grams (0.26 moles) of dimethylaminoethylmethacrylate added dropwise over a period of 2.5 hours with 1 gram (4millimoles) of dicumyl peroxide as polymerization initiator at apolymerization temperature of 140 C. The resultant dimethylaminoethylmethacrylatepoly(e-caprolactone) graft copolymer had a reduced viscosityof 0.28 dl/gm. This product showed no branching and was obtained in agraft efficiency of greater than 40%.

EXAMPLE 14 A sample of poly(e-caprolactone) having a number averagemolecular weight of about 10,600 was prepared by the method described inExample 1 by heating 1,979 grams of e-caprolactone monomer with 21 gramsof diethylene glycol and 0.43 grams of stannous dioctanoate at 180 C.for 24 hours. The number average molecular weight was determined byhydroxyl end group analysis.

A portion of the above-described poly(ecaprolactone) (175 grams) wasplaced in a resin flask equipped with an anchor-type stirrer. Thecontents of the flask were heated to 140C. and agitation begun after thepoly(e-caprolactone) melted. Then 75 grams of n-butyl acrylate and 2.0grams of peroxide were premixed and added to the moltenpoly(e-caprolactone) while maintaining a temperature between 137-142 C.At the end of the reaction the product was transferred to an aluminumtry and allowed to cool to room temperature. A weighed portion of thehard white graft copolymer was dissolved in benzene and precipitated byadding the solution to an excess of heptane. The precipitated polymerwas washed several times with heptane to remove any butyl acrylatehomopolymer that might have formed. The resultant product was a n-butylacrylate-poly(e-caprolactone) graft copolymer containing grafted n-butylacrylate.

EXAMPLE 15 A 204 gram portion of the poly(e-caprolactone) prepared asdescribed in the first paragraph of Example 8, 1.92 grams ofazobisisobutyronitrile and 96 grams of acrylonitrile were dissolved in1,200 grams of benzene. Each of 6 pyrex polymerization pressure bottleswas charged with the above-described mixture purged with nitrogen,capped and placed in a constant temperature water bath at 75 C. Thegraft polymerization was allowed to proceed for 88 hours. The contentsof the bottles were cooled to room temperature, diluted with acetone andprecipitated into an excess of methanol. The products were washed withmethanol and dried at room temperature with a nitrogen purge affordingan acrylonitrile-poly(e-caprolactone) graft copolymer having a reducedviscosity of 0.69 dl/gm. and containing 27.6% acrylonitrile graftcopolymerized as evidenced by a nitrogen analysis.

EXAMPLE 16 In order to demonstrate the compatibility of theacrylonitri1e-poly(e-caprolactone) graft copolymer prepared in Example15 with other polymers, blends of this graft copolymer with polyvinylchloride, polystyrene, poly(methyl methacrylate), styrene-acrylonitrilecopolymer and polyvinyl acetate were made on a tworoll mill at 160 C.using a 5 minute milling time. The milled blends were sheeted from themill and compression molded to form plaques for tensile tests. The datashown in the Table 1 below demonstrates that theacrylonitrile-poly(e-caprolactone) graft copolymer can be readilycombined with a variety of polymers and that it acts as a polymericplasticizer for polyvinyl chloride.

TABLE I M Parts of Parts of Tensile Elonga- Secant Example 16 CopolymerStrength, tion Modulus Graft Co- Blended psi 1%) polymer 100 NoneControl C 3,000 9 78,000

20 parts of 5,300 1 10 154,000

polyvinyl chloride 20 80 parts of 4,100 3 162,000

polystyrene 20 80 parts of 6,000 5 147,000

polymethyl methacrylate 20 80 parts of 3,200 2 177,000

styrene-acrylnitrile copolymer 20 80 parts of 5,300 4 176,000

polyvinyl acetate ASTM D-638-60T EXAMPLE 17 wt. e-caprolactone and 10wt. e-methyl-ecaprolactone were copolymerized at C. using 0.2% stannousacetate as the catalyst and initiator. When the catalyst was added thereaction mixture exothermed to 225 C. within 10 minutes and then thetemperature began to decrease. The copolymer became too viscous to stirso the stirrer was turned off and the reaction system was held in a C.oil bath for approximately 12 hrs. At the end of this time the productwas transferred into glass trays and allowed to cool to roomtemperature. The product was a crystalline solid with a reducedviscosity of 0.86 (0.2 g./dl. in benzene at 30 C.)

200 g. of the above caprolactone copolymer, 85% g. of methylmethacrylate, and 1.7 g. of azobisisobutyronitrile were dissolved in1,140 g. of benzene. The reaction mixture was then charged to 6 pyrexpressure bottles and the bottles were then purged with nitrogen, capped,and then placed in a 60 to 75 C. water bath. The vinyl graftpolymerization was then conducted for 140 hrs. At the end of this timethe bottles were cooled to room temperature and diluted with acetone.The contents were then poured into methanol to precipitate the graftcopolymer. The product was filtered, washed several times with methanoland dried in an air oven at 47 C. The final product was a white solidwith a reduced viscosity of 0.61 (0.2 g./d1. in benzene at 30 C.) andcontained 16.9 wt. methyl methacrylate by weight gain.

EXAMPLE 18 162 g. of the caprolactone copolymer from Example 17, 108 g.of acrylonitrile and 2.2 g. of azobisisobutyronitrile were dissolved in1,078 g. of benzene. The reaction mixture was charged to six pyrexpressure bottles. Thebottles were purged with nitrogen, capped, andplaced in a 75 C. water bath. The graft polymerization was thenconducted for 72 hrs. At the end of this time the contents of thebottles were cooled to room temperature and diluted with acetone. Thecontents were then poured into methanol to precipitate the graftcopolymer. The product was filtered and washed several times withmethanol and dried at room temperature with a nitrogen purge. The finalproduct was a yellow, fluffy, solid with a reduced viscosity of 0.56(0.2 g./d1. in dimethylforamide at 30 C.) and contained 37.5%acrylonitrile by nitrogen analysis.

EXAMPLE 19 509 g. of a 23.6% by wt. benzene solution ofpolyecaprolactone (reduced viscosity 0.65 g./dl. in benzene at 30 C.),135 g. of an 29.6% by weight aqueous solution of sodiumar-(methacryloxyethoxy) benzene sulfonate (NaMABS), 2 g. of benzoylperoxide, 1.0 g. of potassium persulfate, 1.0 g. of sodium bicarbonateand 100 g. of acetone were mixed at room temperature and the reactionmixture was transferred to three pyrex pressure bottles. The bottleswere capped and placed in a 65 C. bath and the graft polymerization wasconducted for 72 hrs. At the end of this time the contents of thebottles were diluted with a mixture of acetone and methanol toprecipitate the copolymer. The product was filtered and worked severaltimes with methanol and then dried. The final product was a granular,while solid with a reduced viscosity of 2.88 (0.2 g./dl. indimethylsulfoxide at 30 C.) and contained 13.5% by weight NaMABS bysulfur analysis.

EXAMPLE 20 Blends of poly(vinyl chloride) having an inherent viscosityof 1.0, a thermal stabilizer, and the graft copolymer described inExample 18 in the amount shown in Table 11 were prepared on a two-rollmill at 160 C. using a 5-minute milling time for blending of thematerials. All aspects (fluxing, banding, bank, roll release,dispersion, and hot strength) of the milling operation were rated asgood. The mill materials were sheeted from the mill, and when cool theywere straw to amber colored, transparent, and smooth. The blendcontaining the lower amount of graft copolymer was rigid and the blendcontaining the larger amount of graft copolymer was flexible. Plaqueswere compression molded from the milled stock at 170 C. and about 1,500psi pressure. The tensile properties of the blends were determined fromthese plaques and the results are tabulated in Table 11.

TABLE 11 Parts Poly(vinyl chloride) 90 55 Parts Exp. 18 Copolymer 45Parts Heat Stabilizer 1.35 0.83 Tensile Properties* Tensile Strength+4800 psi 3500 psi Elongation+ 30% 240% Secant Modulus 1%) ASTM D1530161,000 psi 3100 psi Average of two tests values +Detcrmined hy themethod described below rather than the standard ASTM procedure.

LII

Tensile strength or ultimate strength is the tensile stress at ruptureof a specimen. It is calculated from the load on the specimen at rupturedivided by the original cross-sectional area.

Elongation is the extension of the specimen described above at the pointof break or rupture. It is calculated in the following manner:

% Elongation 1 l 11., x where 1 is the length at rupture and I is theinitial length of the specimen.

Strain rate is the rate at which the sample is being elongated relativeto its original dimension. Thus, if a 1-inch gauge length sample is usedand the cross-head of the testing apparatus is driven at a speed of 1inch per minute, the strain rate is the ratio of gauge length to thisspeed or 1 inch divided by 1 inch per minute, which is a rate of 1 inchper inch per minute. Since we report this value as a percent, multiplythis quantity by 100% and obtain a strain rate of 100% for the examplegiven.

EXAMPLE 21 Blends of Poly(vinyl chloride) having an inherent viscosityof 1.0, a thermal stabilizer, and the graft copolymer, of methylmethacrylate onto an epsiloncaprolactone/methyl-epsilon-caprolactonecopolymer described in Example 17 were prepared on a two-roll mill inthe amounts shown in Table 111. Milling time for combination of theingredients was 5 minutes at C. All aspects of the milling operationwere rated as good. The milled materials were sheeted from the mill, andwhen cool were off-white in color, transparent with a slight haze andsmooth in surface texture. Plaques were compression molded from themilled stock at C. and about 2,000 psi pressure. The tensile propertiesof the blends were determined from these plaques and the results aretabulated in Table 111.

TABLE 111 Parts Poly(viriyl chloride) 90 55 Parts Example 17 copolymers10 45 Parts thermamal stabilizers 1.35 0.83 Tensile Properties* TensileStrength 5,900 psi 2500 psi Elongation 135% 245% Secant Modulus 1%)170,000 psi 1,700 psi Average of two test values Detennined by themethod described in Example 20.

The graft copolymer of Example 17, was also submitted for poly(viny1chloride) plasticizer evaluation at the 70 part graft copolymer per 100parts poly(vinyl chloride) level. The results of this evaluation aregiven in Table IV of this Example.

EXAMPLE 22 1,000 Grams of a 20% by weight benzene solution of thee-methyl-e-caprolactone copolymer described in Example 17 85.7 gm ofstyrene, and 342.8 gm of benzene containing 1.714 gm of dissolvedazobisisobutyronitrile were placed in a beaker and mixed well. Thisreaction mixture was then charged to six pyrex pressure bottles, and thecharged bottles were purged with nitrogen, capped, and placed in a 60 to75 C water bath. The vinyl graft polymerization was then conducted for142 hours. At the end of this time, the bottles were cooled to roomtemperature. The contents were a light amber colored and moderatelyviscous. This product was diluted with acetone and then poured into a91/9 isopropanol/water mixture to precipitate the graft copolymer. Theproduct was then filtered and dried at room temperature. The finalproduct was a white solid that had a reduced viscosity of 0.58 dl./gm.in benzene at 30 C and a concentration of 0.2 g./dl.

A blend containing 10 parts of the above described lactone graftcopolymer and 90 parts of poly(vinyl chloride) having an inherentviscosity (ASTM- Dl243A) of about 1.0 dl./gm. was prepared on a tworollmill at 160 C using a milling time of minutes. 1.5 Parts of aconventional barium-cadium aliphatic acid salt polyvinyl chloride heatand light stabilizer was added to the polymers during the hot blendingoperation. All aspects of the milling operation were rated as good. Thecooled mill sheet of the blend was offwhite, transparent, stiff, andsmooth. A plaque for tensile testing was compression molded at 170 C.The tensile properties of the blend were 1% secant modulus (ASTM D1530)163,000 psi, elongation 150%, and tensile strength 5,300 psi. Tensilestrength and elongation were (determined by the method described inExample 20). For comparison, the host poly(vinyl chloride) had a modulusof 180,000 psi. Although it was not measured, the elongation of the hostpoly(vinyl chloride) would be expected to be less than Thus, the abovedescribed lactone graft copolymer is a good polymeric plasticizer forpoly(vinyl chloride).

The utility of acrylic acid-poly(e-caprolactone) graft copolymers asmetal adhesives was demonstrated by bonding aluminum withpoly(e-caprolactone) having a reduced viscosity of 0.65 dl./gm. ascontrol B and comparing this value with the product obtained in Example8. The peel strength of control B was 3 lbs. per lineal inch as comparedwith 56 lbs. per lineal inch for aluminum bonded with material fromExample 8. Peel strength data were obtained by applying a force to apeeled back section of a aluminum to aluminum laminate bonded witheither the control B or Example 8 graft copolymer and measuring theforce required to peel one lamina from the other with an lnstron TensileTesting Machine. A suitable method for measuring peel strength isdescribed in ASTM D-903-49. The peel strength data referred to abovewere obtained at a 2 about 100 parts of graft copolymer, per hundred ofpolyvinyl chloride, said graft copolymer comprising:

a. lactone polyesters having a reduced viscosity of about 0.2 to 2.0dl./gm., a molecular weight of 15 about 5,000 to 150,000 and repeatingunits having the general formula:

{CHR (CH C o-] wherein R, is H or an alkyl group containing one to aboutsix carbon atoms, and n is an integer having a value of at least 3; and

b. graft copolymerized thereon about 1 to about 20% by weight based onthe weight of said lactone polyesters of an ethylenically unsaturatedmonomer having the general formula:

wherein R is a monovalent radical selected from the group consisting of-H and methyl, R is a monovalent radical selected from the groupconsisting of COOH and COOR, and R is an alkyl radical containing one toabout 18 carbon atoms.

2. Polyblend claimed in claim 1 wherein the lactone polyester (a) ispoly(e-caprolactone) and the monomer (b) is an alkyl methacrylate.

3. Polyblend claimed in claim 2 wherein the alkyl methacrylate monomeris methyl methacrylate.

4. Polyblend claimed in claim 1 wherein the lactone polyester (a) is acopolymer of e-caprolactone and e-methyl-e-caprolactone.

5. Polyblend claimed in claim 4 wherein the monomer (b) is methylmethacrylate. I

6. Polyblend claimed in claim 1 wherein the monomer (b) is acrylic acid.

7. Polyblend claimed in claim 1 wherein the monomer (b) is methacrylicacid.

8. Polyblend claimed in claim 4 wherein the mono-

1. POLYBLEND OF POLYVINYL CHLORIDE AND ABOUT 10 TO ABOUT 100 PARTS OFGRAFT COPOLYMER, PER HUNDRED OF POLYVINYL CHLORIDE, SAID GRAFT COPOLYMERCOMPRISING: A. LACTONE POLYESTERS HAVING A REDUCED VISCOSITY OF ABOUT0.2 TO 2.0 DL./GM., A MOLECULAR WEIGHT OF ABOUT 5,000 TO 150,000 ANDREPEATING UNITS HAVING THE GENERAL FORMULA:
 2. Polyblend claimed inclaim 1 wherein the lactone polyester (a) is poly( epsilon-caprolactone) and the monomer (b) is an alkyl methacrylate. 3.Polyblend claimed in claim 2 wherein the alkyl methacrylate monomer ismethyl methacrylate.
 4. Polyblend claimed in claim 1 wherein the lactonepolyester (a) is a copolymer of epsilon -caprolactone and epsilon-methyl- epsilon -caprolactone.
 5. Polyblend claimed in claim 4 whereinthe monomer (b) is methyl methacrylate.
 6. Polyblend claimed in claim 1wherein the monomer (b) is acrylic acid.
 7. Polyblend claimed in claim 1wherein the monomer (b) is methacrylic acid.
 8. Polyblend claimed inclaim 4 wherein the monomer (b) is acrylic acid.